Exchange processes between a turbulent free flow and a porous media flow are sensitive to the flow dynamics in both flow regimes, as well as to the interface that separates them. Resolving these complex exchange processes across irregular interfaces is key in understanding many natural and engineered systems. With soil–water evaporation as the natural application of interest, the coupled behavior and exchange between flow regimes are investigated numerically, considering a turbulent free flow as well as interfacial forms and obstacles. Interfacial forms and obstacles will alter the flow conditions at the interface, creating flow structures that either enhance or reduce exchange rates based on their velocity conditions and their mixing with the main flow. To evaluate how these interfacial forms change the exchange rates, interfacial conditions are isolated and investigated numerically. First, different flow speeds are compared for a flat surface. Second, a porous obstacle of varied height is introduced at the interface, and the effects the flow structures that develop have on the interface are analyzed. The flow parameters of this obstacle are then varied and the interfacial exchange rates investigated. Next, to evaluate the interaction of flow structures between obstacles, a second obstacle is introduced, separated by a varied distance. Finally, the shape of these obstacles is modified to create different wave forms. Each of these interfacial forms and obstacles is shown to create different flow structures adjacent to the surface which alter the mass, momentum, and energy conditions at the interface. These changes will enhance the exchange rate in locations where higher velocity gradients and more mixing with the main flow develop, but will reduce the exchange rate in locations where low velocity gradients and limited mixing with the main flow occur.

中文翻译：

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障碍物、界面形式和湍流：不同界面土壤-水蒸发的数值分析

湍流自由流和多孔介质流之间的交换过程对两种流态中的流动动力学以及将它们分开的界面都很敏感。解决这些跨不规则界面的复杂交换过程是理解许多自然和工程系统的关键。将土壤-水蒸发作为感兴趣的自然应用，考虑到湍流自由流动以及界面形式和障碍，对流态之间的耦合行为和交换进行了数值研究。界面形式和障碍物将改变界面处的流动条件，创建流动结构，根据它们的速度条件和与主流的混合来提高或降低交换率。为了评估这些界面形式如何改变汇率，界面条件被隔离并进行数值研究。首先，比较平坦表面的不同流速。其次，在界面处引入了不同高度的多孔障碍物，并分析了发展的流动结构对界面的影响。然后改变该障碍物的流动参数并研究界面交换率。接下来，为了评估障碍物之间流动结构的相互作用，引入了第二个障碍物，以不同的距离隔开。最后，修改这些障碍物的形状以创建不同的波形。这些界面形式和障碍中的每一种都会在表面附近产生不同的流动结构，从而改变界面处的质量、动量和能量条件。